License, verbatimCC0
The Metropolitan Museum of Art: Open Access, Creative Commons Zero (CC0). Flagged isPublicDomain=true in the museum's own record.
Francesco Galli Bibiena. Designs for the Theater at Nancy: View of Half the Proscenium and a Half a Section of It; End of the Ceiling; and Ground Plan, 1659–1739. The Metropolitan Museum of Art.